Analysis of the phenotypic adaptability and stability of strains of cowpea through the GGE Biplot approach

Abstract

The cowpea is produced in different environmental conditions in several regions of Brazil. It is crucial to select and develop cultivars that attend to the regional requirements with high productivity, adaptability, and stability, due to the interaction between the genotype and the environment. This research aimed to select strains of cowpea for the simultaneous presence of high genotypic productivity, adaptability, and stability in the North-eastern region of the state of Rio de Janeiro (Brazil) by the GGE-Biplot method. The study assessed 27 genotypes: 23 strains and four cultivars, in six environments of the North-eastern region of the state of Rio de Janeiro, during the years 2016, 2017, and 2018. The experimental design was a randomized block design with four repetitions. The GGE-Biplpot method assessed the genotypic adaptability and stability, by the use of the statistical software R. The interaction between the environment and the genotypes was complex, and the general average for the productivity of the grains was 1231.98 kg/ha. GGE-Biplot method was efficient in identifying the best strains to be suggested for the use in the North-eastern region of the state of Rio de Janeiro. The strains (9), (3), and (6) were classified as ideotypes due to their superior performance compared to the general average, and their stability. Their performance overcame the control cultivars BRS Tumucumaque, BRS Imponente, BRS-Itaim e CB-27.